Dynascan^TM - Insight was found in Jyrki Kauppinen’s excellent paper from Applied Optics 34, 6081 (1995), which discusses a series of related interferometer designs based on rotation or tilt of plane mirrors. This slide shows Perkin-Elmer’s Dynascan^TM design which uses complementary reflections from two plane mirrors in each arm of the interferometer to produce beams of constant propagation angle, irrespective of the tilt angle of the platform. The beams of constant angle can be reflected exactly back on themselves by plane mirrors at the end of each arm.